A mobile telephone which is logged-in in a radio cell of a mobile radio network continuously exchanges radio waves with a fixed base station of the mobile radio network.
If other electronic devices are situated in the transmission range of the mobile telephone, then the radio waves can cause interference in these devices.
The use of mobile telephones in hospitals is prohibited for this reason, for example. In aircraft the use of private, radio-based communication facilities is not permitted at all nowadays for safety reasons. It is suspected that the radio waves from the private portable devices could disrupt the avionics system of the aircraft.
On the other hand, the use of mobile communication terminal facilities is constantly increasing. There is a growing demand to be able to utilize private communication facilities, in particular those based on the widely used GSM standard (Global System for Mobile Communication), in a manner which is as simple and unrestricted as possible even during a flight.
With the introduction of the “GSM on-board system”, the use of private mobile telephones is intended to be permitted in aircraft in future with certain restrictions. For safety reasons, it is not possible in this situation to rely exclusively on the willingness of passengers to cooperate in turning on their mobile telephones only during the flight phase of the journey and turning them off independently during the safety-critical takeoff and landing phases. In order to satisfy the technical safety requirements, it initially appears possible to turn off the base station of the radio cell in the aircraft during takeoff and landing under the control of a deactivation signal provided by the aircraft electronics. In this situation, it would however be disadvantageous that mobile radio stations on the ground would be visible to switched-on mobile telephones as of a particular flying altitude and would stimulate them to emit radio waves.
A mobile communication system is disclosed in WO 9428684 A1 in which the interference-free use of private mobile telephones on board an aircraft or a ship is made possible by the fact that the mobile telephones are connected by means of electrical cables or an infrared interface to the on-board communication system. It is also disadvantageous here that the safety on board depends on the willingness of the passengers to cooperate. Moreover, the cabling or the infrared interface is intricate and elaborate.